FILE - New Jersey State Capitol

The New Jersey State Capitol in Trenton, New Jersey.

Ninety percent of state legislative incumbents in New Jersey are seeking re-election in 2021. Of these 108 incumbents, 79% – 85 legislators – will advance to the general election without a primary challenge, according to Ballotpedia’s primary election competitiveness analysis.

The remaining 23 incumbents – nine Democrats and 14 Republicans – will face contested primaries on June 8, 2021.

When an incumbent faces a contested primary, there is the chance he or she might be defeated before the general election, typically guaranteeing the seat to a newcomer. These defeats – along with retirements and general election losses – contribute to the overall incumbent turnover during each election cycle.

The most common cause of incumbent turnover is retirement, which, over the past decade, accounted for 70 percent of all state legislative turnover. Primary election defeats – at 10 percent – were the most uncommon cause of turnover.

Primary election defeats in New Jersey are especially rare. Since 2011, only one state legislative incumbent has been defeated in one: Assm. Joe Howarth, who lost in a 2019 Republican primary.

Contested incumbent primaries became more common in New Jersey during the 2017 state legislative elections. In 2019, the state saw a decade-high rate with around one-third of all incumbents facing primary challenges. The rate decreased to around one-fifth of all incumbents facing contested primaries in 2021 but remains higher than rates from the first half of the past decade.

Virginia is also holding state legislative elections in its House of Delegates in 2021. Based on preliminary data, the state is slated to see a decade-high rate of incumbents facing contested primaries at 18.1%. Out of the 100 incumbents, 94 are seeking re-election, 17 of whom will face contested primaries. Parties in Virginia use a mixture of primaries and conventions to select nominees. All primaries will take place on June 8 whereas convention dates are selected by district parties. Ballotpedia will update its primary competitiveness data for Virginia as it becomes available.